Porous metallic tipe



C. N. LOHREY POROUS METALLIC TYPE June 16, 1942.

Original Filed July 9. 1938 Carl N. Lohrey tor By M W lnven His AttorneyReissued June 16,1942

' UNITED STATES PATENT OFFICE National Cash Register Company, Ohio, acorporation of Maryland Dayton.

Original No. 2,199,265, dated April 30, 1940, Serial No. 218,377, July9, 1938. Application for reissue .Inne 19, 1940, Serial No. 341,397

13 Claims.

This invention relates to. printing members and more particularly toimpregnated printing members of porous metallic structure.

The principal object of this invention is to provide type, type-wheelsand other printing members of porous metallic structure wettable by andcapable of absorbing a relatively large amount of liquid substance, suchas ink or sensitizing fluids, which is available for rendering a greatnumber of inked or sensitized impressions without replenishment of thesupply.

Another object of the invention is to provide an ink absorbing metallicprinting member of highly porous construction molded of powdered metalsand a subliming substance which is removed in a sintering operation.

Another object of the invention is to provide a metallic printing memberof porous construction impregnated with absorbed ink, whereby the inkwhich has been transferred from the pores on the type face to thematerial receiving the impression, on the last printing operation, isreplaced from the absorbed ink supply by capillary diffusion.

Another object of the invention is to provide a metallic printing memberof ink porous construction possessing the qualities of hardness,rigidity, and malleability.

Another object of the invention is to provide a porous metallicconductor of ink having a porous printing face integral therewith, saidpores being invisible to the unaided eye.

Another object of the invention is to provide an ink impregnatedmetallic type member of porous structure which is kept evenly saturatedfrom a self-contained ink supply, by capillary difi'usion.

Another object of the invention is to provide a porous metallic typewheel having a self-enclosed ink well, said ink being conducted tothetype face by interconnecting capillary pores.

Another object of the invention is to provide type of porous metallicstructure, that may be inked from inside the type face.

Another object of the invention is to provide a metallic type that willabsorb and hold a supply of ink suflicient for a great number ofimpressions, which ink may be replaced by absorption when exhausted.

With these and incidental objects in view, the inventionincludes'certain novel features of construction and combinations ofparts, the essential elements of which are set forth in appended claimsand a preferred form or embodiment of which is hereinafter describedwith reference to the drawing which accompanies and forms a part of thisspecification:

or said drawing:

Fig. 1 is a perspective view of a typical type wheel having a well forfluids enclosed therein.

Fig. 2 is a cross-section through the wheel shown in Fig. l,perpendicular to its axis of rotation.

Fig. 3 is a vertical cross-section through a printing member mounted ina handle.

Fig. 4 represents the type levers, type basket and platen of a typicaltypewriter, showing a wick method of saturating porous type.

The application of ink to the printing face of metallic type hasheretofore required contact of the type with an inking surface afterevery impression, because all of the ink or nearly all of the ink on thetype face is transferred to the printed material when the impression ismade. Methods have been devised to overcome the necessity of inking suchtype on each inked impression among which are the use of an inked ribbonor a sheet of carbon paper interposed between the type and the recordmaterial. In such methods using an interposed inking substance, theimpression is faulty due to the thickness of the material so placedbetween the type and the material to be printed upon.

This invention provides a method of supplying ink to type faces from anink supply contained in the pores of or conducted through pores of thebody of the type, making it unnecessary to ink the type faces on eachprinting operation or to have an intervening ink carrying materialbetween the type and the record material. The ink removed from theprinting face is constantly replaced from within the type member by acapillary duflfusing action.

The material used in the preferred embodiment of applicant's inventionis composed of metal of a hardness comparable to that ordinarily usedfor metal type but having therein interconnecting capillary porescapable of absorbing and conducting fluids in all directions. Theabsorbed fluids are retained in thebody pores of the type by capillaryaction, except that the surface fllm may be transferred to material usedin printing by an ordinary printing operation. The ink removed from thepores opening on the type face is then restored by capillary actionwhich tends constantly to diffuse the absorbed fluid evenly throughoutthe type body.

The method of manufacturing porous metallic structures is well known,the metals used having different characteristics of hardness to resistwear and also corrosive action of the fluid used,

porosity, and difl'ering as to the wetting action and its action towetting must suit the fluid to be used.

Manufacture of porous metallic type suitable for absorbing ink A porousmetallic structure composed of 70% powdered nickel and powdered copper,being the approximate analysis of Monei metal, has

been found most suitable for use with dye inks as it is wettable by suchfluids, absorbs a considerable quantity of them, and is hard enough toresist wear through use of corrosion.

A mixture of powdered copper and powdered nickel in the proportionsstated is molded under great pressure in molds formed so that the typemembers produced have impressed thereon the characters desired. The typemembers so molded may be further treated by sintering in an inert gas toperfect the union of the adjacent granules of metal by heat. There willbe left throughout the molded and sintered product a multitude ofinterconnecting pores capable of absorbing dye ink from the surface. Torender the molded structure even more porous, some material thatsublimates in the presence of heat may be added in the form of powder.to the powdered copper and powdered nickel so that when the sinteringoperation is completed the space formerly occupied by the sublimedmaterial serves as additional pore space for the storage of ink. Themolded product may be struck by a forming tool to shape it withoutdestroying its porosity.

The pores so produced extend to the surface of the molded product andconsequently the fluid at the open ends of the said pores are subject toordinary surface tension phenomena. The result is that the fluidsabsorbed by the molded product will not be dissipated unless the surfacefilm is broken by a printing impression, in which event a portion of thesurface him will be transferred to the article to be printed. Thisremoved surface film is restored at once by the diffusion of the inkcontained in the pores, due to capillary action.

The pores so formed are so small as to be invisible to the unaided eye.The small size of the pores allows only a small portion of ink to betransferred on a printing operation, eliminating any possibility ofsmudging or blotting. The capillary forces in such small pores are sogreat as to hold the fluid in the pores against gravitational force, andthe moving forces caused by rotation or hammering normal to printingoperations.

Means of supply ng type members with fluids The wheel form of embodimentof the invention is illustrated in Figs. 1 and 2 which represent aporous metallic type wheel in mounted on a shaft ll having a plurality'of type faces If on its circumference. Within the body of the wheelisan annular font I3 adapted to hold fluids as shown in Fig. 2. A plug IIis provided giving access to the font from the circumference of thewheel for fllling with fluid. In this particular form the fluidssaturate the porous printing wheel by contact therewith. Capillaryforces acting on the surface film formed at the external pore openingskeep the fluid within the wheel, except when the surface film is brokenby contact with the material to be printed.

A modified form of embodiment of the invention is shown in Fig. 3 whichconsists of a large bodied porous metallic printing member ll having acorrespondingly great capacity for absorbing and storing ink in itspores when saturated. A removable handle [8 is provided to protect thehands of the user from contact with the printing member. With thisconstruction the member I! is used repeatedly until exhausted of fluidand then is resaturated.

Another desirable embodiment is shown in Fig. 4 wherein the porousmetallic type I! is fastened to the type levers l8 of a typicaltypewriter. Normally the body of the type II rests on a wick I! which ishalf submerged in fluid 20 held in a reservoir 2|. The reservoir andwick take the place of the usual type basket. The wick I8 is saturatedwith the fluid and whatever fluid is removed from the type body by thetype face in the printing operation is replenished by the wick as thetype rests thereon. A screen support 22 maintains the wick in apartially submerged condition to prevent splashing. A platen 23 isillustrated as holding record material 24 in the usual manner. In thisconstruction the same wick can serve a plurality of printing members.

The ink used with porous type should preferably be non-volatile and freefrom pigment, or corrosive action on the pores, to prevent clogs g.

It is to be understood that applicant is not confining his invention tothe particular combination of metals named nor their use solely with thefluids mentioned, although the metals mentioned have been foundparticularly suited to be used with dye inks.

While the form of mechanism herein shown and described is admirablyadapted to fulfill the objects primarily stated, it is to be understoodthat it is not intended to confine the invention to the one form orembodiment herein disclosed, for it is susceptible of embodiment invarious forms all coming within the scope of the claims which follow.

What is claimed is:

l. The method of making porous printing type consisting of mixing sevenparts of powdered nickel and three part of powdered copper; and moldingthe mixture under great pressure until a rigid structure is formed.

2. As a new article of manufacture, a product produced in accordancewith the method of claim 1.

3. The method of making porous printing type consisting of mixing sevenparts of powdered nickel and three parts of powdered copper: molding themixture under great pressure until a rigid body is formed; and sinteringthe molded body in an inert gas.

4. As a new article of manufacture, a product produced in accordancewith the method of claim 3.

5. The method of making porous printing type consisting of mixing sevenparts of powdered nickel, three parts of powdered copper, and a powderedsubliming material molding the mixture under great pressure; andsintering the molded body in an inert gas to perfect the union 01 theconstituent metal particles and to vaporize and expel the sublimingmaterial.

6. As a new article oi manufacture, a product produced in accordancewith the method of claim 5.

7. The method of producing a printing member which consists in the stepsof forming the member by joining powdered metal into a single porousmass and then impregnating said mass with a non-corrosive recordingfluid.

8. The method of producing a printing member which consists in joiningpowdered metal, which is wettable by but not corroded by ink, into arigid porous mass; next sintering said mass in an inert gas to perfectthe union of the powdered metal; and then impregnating the porous masswith an ink oi! a type which will not clog the pores of the metal.

9. A printing member 01 joined powdered metal forming a singlecontinuous porous malleable body containing a network 01'interconnecting pores extending in all directions between the joinedparticles 01' metal and capable or conducting and retaining ink to beused in a printing operation.

10. A printing member oi closely united powdered metal forming a rigid prous body, said member having thereon indicia from which impressions aremade, said pores in said body holding a supply of ink and said poresextending through the body in all directions from said indicia andoperating to conduct ink quickly by capillary action from adjacent partsof said body to said indicia to restore uniform ink density in the bodyafter ink has been removed from the indicia when an impression has beenmade.

11. The method of producing a printing member which consists in moldingpowdered metal under pressure to form a rigid mass having poresextending therethrough in all directions between the particles ofpowdered metal; next, fusing the rigid mass of powdered metal to form analloy which retains the pores that were formed when the powdered metalwas molded; and then impregnating said member with an ink or a typewhich will not clog the pores in the metal.

12. As a new article of manufacture, a product produced in accordancewith the method of claim 11.

13. As a new article of manufacture, a product produced in accordancewith the method of claim 8.

CARL N. LOHREY.

